<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>

  <div id="render"></div>

  <script type="text/babel">
    class Clock extends React.Component {
      constructor() {
        super()
        this.state = {
          isLogin: false
        }
        this.changeLogin = this.changeLogin.bind(this)
      }
      changeLogin() {
        this.setState(res => ({
          isLogin: !res.isLogin
        }))
      }
    }

  </script>

</body>

</html>